陶粒混凝土的破坏损伤数值模拟

Numerical simulation of rupture damage of ceramsite concrete

全轻陶粒混凝土作为一种常见的轻骨料混凝土,具有非常好的工程前景,特别是在高层建筑和装配式结构方面。然而,目前对于陶粒混凝土的研究主要在宏观层次。在细观层次上,将陶粒混凝土视为由陶粒、水泥砂浆、陶粒-水泥砂浆界面过渡区构成的三相复合材料,采用M-T均匀化理论,通过对比试验结果验证模型参数的准确性。同时,建立陶粒混凝土细观二维模型,进一步研究陶粒混凝土的破坏损伤机理及裂缝发展规律。结果表明,通过合理的陶粒混凝土配合比设计,在陶粒等体积取代碎石下配制出可以满足LC35强度等级的陶粒混凝土,且符合规范对于轻骨料混凝土的密度要求。通过对陶粒混凝土二维150 mm×150 mm的构件进行模拟,发现陶粒混凝土的抗压破坏是从界面过渡区开始产生裂缝,随后裂缝贯穿陶粒并进一步扩展直至陶粒混凝土达到极限荷载强度;通过对陶粒混凝土劈裂抗拉的数值模拟,陶粒混凝土的端部裂缝一部分贯穿骨料,一部分沿着骨料与砂浆的界面区域发展。

As a common lightweight aggregate concrete,full lightweight ceramsite concrete has a very good engineering prospect,especially in high-rise buildings and assembled structures.However,the current research on ceramsite concrete is mainly at the macro level.On the mesoscopic level,the ceramsite concrete is regarded as a three-phase composite material composed of ceramsite,cement mortar and ceramsite-cement mortar interface transition zone.The M-T homogenization theory is used to verify the accuracy of the model parameters by comparing the experimental results.At the same time,a mesoscopic two-dimensional model of ceramsite concrete was established to further study the damage mechanism and crack development law of ceramsite concrete.The results showed that through the reasonable mix design of ceramsite concrete,ceramsite concrete that can meet the LC35 strength grade and meet the density requirements of lightweight aggregate concrete can be prepared under the equal volume of ceramsite instead of gravel.Through the simulation of the two-dimensional 150 mm×150 mm component of ceramsite concrete,it is found that the compressive failure of ceramsite concrete begins to crack from the interface transition zone,and then the crack penetrates the ceramsite and further expands until the ceramsite concrete reaches the ultimate load strength.Through the numerical simulation of splitting tensile strength of ceramsite concrete,some of the cracks at the end of ceramsite concrete run through the aggregate,and some develop along the interface area between aggregate and mortar.